Often, customers are in search of a “non-slip” tile. While certain tiles have more texture than others, the truth is, ALL hard surfaces are slippery when wet. So whether your flooring is laminate, wood or tile; contaminants such as dirt, water, soap residue, oil, or grease can change the amount of slipperiness on these surfaces. There are many factors that affect the possibility of a slip occurring on a tile such as, the material of the shoe sole and the degree of its wear and the presence and nature of surface contaminants. These factors are not limited to tile either, because all hard surfaces are slippery when wet!
The flooring industry uses coefficient of friction ratings as a guideline to determine the slip resistance of ceramic and porcelain tiles. A higher coefficient of friction indicates increased resistance of movement over the floor tile. The coefficient of friction measurement is an evaluation of a tile surface under known conditions using a standardized method.
So what exactly does this mean? In short, it can provide a useful comparison of flooring surfaces, but it does not predict the likelihood a person will or will not slip on a tiled surface! There are two methods in which the coefficient of friction is measured in. Until recently, coefficient of friction was measured in static coefficient of friction (SCOF). This is when a material is at rest and what force it takes to begin sliding over the floor surface. Here are some of the specs for my fellow tile gurus:
Static Co-Efficient of Friction (SCOF) – ASTM-C1028 the ratio of the force necessary for a surface to begin sliding over another divided by the weight of an object.
SCOF - Recommendations for slip resistance by ADA and OSHA:
ADA= Wet/Dry 0.6 or greater
ADA Ramps= 0.8 or greater
OSHA= Wet/Dry 0.5 or greater
OSHA Ramps= Not Test Rating
This method has been helpful, but at times can be unrealistic. To better help depict real life situations, a new method of determining slip resistance has been devised. This method being dynamic coefficient of friction (DCOF) also called kinetic coefficient of friction. This is helpful because the measurement is similar to the natural movement of walking across these floor surfaces and, hence kinetic movement!
Dynamic Co-Efficient of Friction (DCOF) Sometimes called kinetic COF. This is the ratio of the force necessary to keep a surface already in motion sliding over another divided by the weight of an object.
DCOF – Specifications when measured with the BOT 3000 per the procedure in the A137.1 standard. ANSI A137.1= Wet: 0.42 DCOF
So when you’re shopping for tile with slipperiness in mind, remember that the risk of a slip can be diminished by installing tiles with a structured/textured surface, mosaic tiles for more grout traction, or certain unglazed quarry tiles. The industry has tried to measure slipperiness with coefficients of friction; however it is not an accurate depiction of how slippery a floor surface can be. Because many variables affect the risk of a slip occurring, the COF should not be the only factor in determining the appropriateness of a tile for a particular application!